Chloramphenical (RNHCOCHCl2) undergoes dechlorination to form two products by a glutathione dependent enzyme or enzymes in 100,000 x g supernatant of the rat liver. These metabolites have been identified by gas chromatography mass spectrometry as CAP aldehyde (R-NHCOCOH) and a CAP oxamyl derivative (R-NHCOCO-) which is believed to be a GSH thioester.